What is the WHY

I'm currently reading "The Amazing Adventures of Kavalier and Clay" by Michael Chabon. It's an engaging story focusing on two cousins in the late 1930's in New York who are working to break into the comic book industry as artists and writers.

As they begin to brainstorm potential characters for their first big pitch to a publisher, they start by listing superpowers, possible names, and costume designs, until Sammy "experienced a moment of global vision, one which he would afterward come to view as the one undeniable brush against the diaphanous, dollar-colored hem of the Angel of New York to be vouchsafed to him in his lifetime." Here's how Sammy shares his revelation with his cousin Joe:

"The question is why."
"The question is why," Joe repeated.
"Why is he doing it?"
"Doing what?"
"Dressing up like a monkey or an ice cube or a can of fucking corn."
"To fight the crime, isn't it?"
"Well, yes, to fight crime. To fight evil. But that's all any of these guys are doing. That's as far as they ever go. They just... you know, it's the right thing to do, so they do it. How interesting is that?"
"I see."
"Only Batman, you... see, yeah, that's good. That's what makes Batman good, and not dull at all, even thought he's just a guy who dresses up like a bat and beats people up."
"What is the reason for Batman? The why?"
"His parents were killed see? In cold blood. Right in front of his eyes, when he was a kid. By a robber."
"It's revenge."
"That's interesting," Sammy said. "See?"
"And he was driven mad."
"Well..."
"And that's why he puts on the bat's clothes."
"Actually, they don't go so far as to say that," Sammy said. "But I guess it's there between the lines."
"So, we need to figure out what is the why."
" 'What is the why,' " Sammy agreed.

They were focused on the wrong starting point. The WHY is much more important than the WHAT or the HOW. Good advice for all creators. What examples do have where you focused on the WHAT or the HOW when you would have been more productive to start with the question WHY? Share your experience in the comments below.